1. Field of the Invention
The present invention relates to farming equipment in general and sugar cane planters in particular. The present invention is even more related to such planters having fully automatic, hydrostatic, pressure sensing systems for planting full stalk seed cane in three or more rows at once.
2. General Background
In the sugar cane industry, it is necessary to periodically replant the cane field with stalks in full lengths or in short length sections. The typical full stalk planter is a towed vehicle having a wheeled or tracked chassis and a bed containing a large number of stalks to be planted held in a semi-vertical position. Typically, these stalks are force fed toward a rotating drum as the result of an inclined barrier moving the whole load in the direction of the rotating drum. The drum is usually mechanically or hydraulically driven, and works in combination with a hydraulic ram or ratchet device for pushing the incline barrier and the cane toward the drum. The rotating drum is sequenced in a manner which controls the number of stalks that are allowed to be laid in the prepared row in relationship to the speed of the chassis as it moves along the furrow. In the past such planters have been restricted to planting only one row at a time due to the machines inability to control the flow of stalks to the distribution drum. In most cases as exhibited by Davis in U.S. Pat. No. 4,653,411, Longman U.S. Pat. No. 4,106,669; Allain U.S. Pat. No. 3,946,899, and Dugas U.S. Pat. No. 4,084,465; an operator is positioned on the side or directly behind the rotating drum to control the distribution process. In some cases a purely mechanical means for distributing full length cane is employed as exhibited by Longman in U.S. Pat. No. 3,468,441. In any case such distribution of full length cane stalks has been limited to one or two rows. It should also be noted that even where two row planters are disclosed, the row directly beneath the planter is not planted requiring multi-passes by the planter over the same rows.
The existing mechanical sugar cane planters have several problems which cannot be easily overcome by the average cane farmer; hence, approximately half of the sugar cane planted in the United States is done by hand. The other half is done with machinery, which is often not understood by the average field worker. As a result, such sophisticated systems require expensive maintenance service often resulting in unacceptable delays during planting. Even with the use of sophisticated electrical over hydraulic distribution and feeding systems and the use of an onboard operator, the operator, the system, or both often can not react fast enough to changing conditions to produce the kind of consistency normally resulting from hand planting. Due to the increasing cost of labor and the need to improve overall efficiency, an improved method of controlling such planting is required.
Existing drum type planters rely on the dispensing drum turning at a constant speed to meter the seed cane being planted. Usually the planter is towed at a constant speed to produce a uniform distribution. Problems occur with such systems, when the cane is loaded, often in a very random manner and in some cases mixed with vines and other vegetation and a good deal of dirt. Thus, the consistency varies within the load and with each new load. Such inconsistencies causes large clumps of tangled stalks to be compressed against the primary distribution drum resulting in jamming. Therefore, systems which rely on constant hydraulic fluid flow must compensate with wildly oscillating pressures to maintain the required torque to the rotating drum head. Such pressures may vary from 400 psi to 2400 psi within one revolution of the drum. Thus, typical pressure relief and compensator valves are required to operate hundreds of times per minute. This has proven to be impractical. Therefore, farmers attempt to minimize this effect by setting the valves with as wide a range as possible, thus sacrificing control of the planting rate, creating planting skips on the low end and piles on the high end. These systems are incapable of operating at intermediate ranges. To overcome these problems, a system is clearly needed which will deliver the cane to the distribution drum in a uniform manner and provide an efficient non-complicated method of automatically sensing the distribution of the stalks in multiple rows.